In addition to his Japanese records, Yamanaka had two American Records in the 200 and 400 meter freestyle and won the U.S. National AAU Championships in those events. He beat Hall of Fame swimmer George Breen in Olympic competition but often failed against Hall of Famer Murray Rose.
Rose's birthday was six days before Yamanaka's and Murray used to kid him that out of respect for his elders he should let Rose finish first. He came in second in the 1956 and 1960 behind Hall of Famer Australians Rose and Konrads.
Yamanka's coach used the pebble method to train him. Whenever Yamanka loafed in practice he would feel a pebble bounce off his back to remind him the coach was watching him. After the workout Yamanaka had to pick the pebbles from the pool bottom.